The present disclosure relates generally to the field of golf balls. Specifically, the present disclosure relates to a golf ball having at least one dimple, where the dimple is capable of changing in such a way as to alter the play characteristics of the golf ball.
The game of golf is an increasingly popular sport at both the amateur and professional levels. A wide range of technologies related to the manufacture and design of golf balls are known in the art. Such technologies have resulted in golf balls with a variety of play characteristics. For example, different golf balls are manufactured and marketed to players having different golfing abilities, such as different swing speeds.
Similarly, a golfer may use different golf balls having different play characteristics depending on, for example, the golfer's preferences or the play conditions. For example, different dimple characteristics may affect the aerodynamic properties of the golf ball during flight, or a difference in the hardness of the cover layer may affect the rate of backspin. With regard to the dimples in particular, a wide variety of dimple characteristics are known to affect the golf ball's aerodynamic properties, such as the dimple pattern, dimple shape and dimple depth.
Ideally, the dimples should be designed to achieve the greatest possible flight distance by achieving reduced drag and increased lift. As is generally known, drag is the air resistance that opposes the golf ball's flight direction. Drag is caused by the difference between high air pressure in front of the golf ball and low air pressure in the golf ball's wake. The dimples cause a thin boundary layer of air bordering the golf ball's outer surface to flow in a turbulent manner. The turbulent boundary layer moves the separation point backward, so that the boundary layer stays adjacent to the golf ball further along the ball's outer surface. As a result, the area of the wake is reduced and the pressure behind the ball is increased. Drag is thereby reduced, and the golf ball achieves increased flight distance.
As is also generally known, lift is an upward force on the golf ball that is created by a difference in pressure between the top of the ball and the bottom of the ball. Due to the golf ball's backspin, the top of the ball moves in the same direction as the airflow, which moves the air separation point to a location further backward. Conversely, the bottom of the ball moves against the airflow, which moves the separation point forward. This asymmetrical separation creates an arch in the flow pattern, whereby air that flows over the top of the ball moves faster than the air that flows along the bottom of the ball. As a result, the air above the ball is at a lower pressure than the air underneath the ball. This pressure difference results in the overall force, lift, which is exerted upwardly on the ball. Lift therefore causes the golf ball to achieve increase flight distance, as the upward lift force keeps the golf ball in the air for a longer period of time.
Dimple depth in particular can significantly affect the aerodynamics of the golf ball's flight. As is generally known, shallower dimples tends to result in the golf ball rising higher during flight. Conversely, the deeper the golf ball dimples, the lower the golf ball flight. It is believed that these tendencies are caused by decreased lift due to greater turbulence of the air inside deeper dimples, although many different aerodynamic phenomenon likely come into play.
Consequently, a golfer may desire to use a golf ball having shallow dimples or a golf ball having deeper dimples at different times, depending on a variety of factors. For example, the weather, the golfer's athletic abilities, the amount of back spin applied, and the particulars of the equipment being used may all affect whether shallow dimples or deeper dimples will better achieve the greatest total flight distance. Specifically, for example, a golfer may prefer to use a golf ball with deep dimples under high wind conditions, because such a golf ball will fly lower to the ground and therefore not be as affected by the wind. On the other hand, a golf may prefer to use a golf ball with shallow dimples under low winds conditions, in order to achieve a slightly increased total flight distance, all other factors being equal.
Amateur golfers generally prefer to minimize the costs of purchasing new golf balls. However, a golfer may be required to purchase several sets of golf balls in order to achieve different play characteristics. Namely, a golfer may be required to purchase one set of golf balls with shallow dimples and another separate set of golf balls with deeper dimples. The need to purchase, store and carry several sets of golf balls in order to achieve a variety of play characteristics presents an inconvenience to the golfer, as well as increased costs.
Therefore, there is a need in the art for a system and method that addresses the shortcomings of the prior art discussed above.